Down with Waste Water, Up with Potable Water

Editor's Note: This issue of CSE inaugurates a new bimonthly feature in our Professional Practices pages: The Role of the Engineer. This month, plumbing specialists offer some thoughts on their place in the engineering community—duties and responsibilities, how they are perceived by peers, and how their design team role could be improved.


Anyone can do plumbing, or so it's been said. What do you need to know? "You've got to have hot and cold running water, and everything flows according to Newton's Law of Gravity."

Of course, in the last part of this quip, those aren't the words that one usually hears. Nevertheless, it 's close enough to the standard engineer's put-down for plumbing system designers. A common attitude around the building industry has the plumbing engineer doing little more than piping water and removing waste on any given project.

Even in the world of consulting engineering, it would seem that too many others are unaware of all the design aspects the plumbing engineer is responsible for. Surprisingly, even many HVAC and fire-protection engineers don't know.

Today's plumbing engineers are not only tasked with safety issues, but they must also provide services and expertise that are responsive to environmental concerns, the community, the owner, the architect and virtually all other trades involved in bringing a project to completion.

Life safety and the welfare of the environment could be called the "high profile" aspects of the plumbing engineer's role. But while fire protection, filtration, water conservation, backflow prevention and water purification are all very important, the plumbing engineer is accountable for much more.

Besides the obvious—supplying water and removing waste—plumbing designers are responsible for a plethora of associated systems, with at least as many applications.

Hospitals, universities, industrial plants and pharmaceutical companies all require specialized systems. They all look to the plumbing engineer to provide those viable systems, while all the time adhering to allotted budgets and dealing with space limitations.

In most cases, the engineering that goes into specialized applications is very detailed, and consequently, time-consuming. Special attention must be given to virtually every aspect of the materials to be used. Flow characteristics for the various fluids, pumps and pressure dynamics, as well as temperature and temperature mixing, are some of the less obvious, but essential data that plumbing engineers must analyze to design efficient systems.

Specification is critical, from the largest equipment selections—including pumps, valves and other devices—right down to the smallest piping and fittings. Plumbing engineers are already required to decide which are the best manufacturers or product lines for a given project. And not infrequently, they must go through again and reinvestigate when a mechanical contractor submits an alternate or substitute for the items. It is the plumbing engineer's responsibility to ensure that the final product is in compliance with the original design and specification.

While plumbing design professionals are most likely to work closely with other mechanical engineers, interaction with all other design team members—even architects—is key. We're called upon to work with fire-protection engineers for life-safety systems interfaces and with electrical engineers for equipment such as electric pumps. Moreover, we are always encountering issues of infrastructure with electrical and lighting designers. For example, lighting layouts have to be coordinated with sprinkler systems. Everything is interrelated.

Even the smallest architectural changes can have a compounding effect on the plumbing design. A seemingly minimal last-minute change, such as moving a plumbing fixture from one wall or area to another, can affect design and installation work on at least three floors. And don't forget: In many cases, the engineer does his or her own drafting (CAD or otherwise) and has to re-plot for the changes.

This brings us to an important point about plumbing engineers. We must cross boundaries to ensure continuity between trades, comply with a myriad of codes, statutes, supplements, amendments and jurisdictions, and all the while, be responsible for the coordination and proper implementation of it all. And should anything be forgotten, there will always be someone lurking in the background to cast blame and a contractor with a sharp pencil to charge an extra.

If plumbing designers are sometimes looked down upon by their engineering colleagues, part of the reason might be the lack of a specific and official plumbing curriculum in engineering schools. But no matter what anyone thinks, a career in plumbing design has much to recommend it. There are so many different situations in plumbing that one deals with something new all the time.

So, on behalf of plumbing engineers everywhere, know this: No matter how decorative an atrium or foyer, no matter how artfully illuminated or trendy the light fixture, no matter how comfortable the air conditioning feels on a hot summer day, there is nothing greater for peace of mind and well-being than a visit to your favorite water closet—knowing that Elvis has left the building.

A Conversation with Plumbing Designers

CONSULTING-SPECIFYING ENGINEER: You mention that specification is critical. Can you provide some examples or elaborate on this?

BALDINO : For example, if we are doing hospitals, with chemical waste to dispose of, the wrong type of piping material could be disastrous. The piping might decompose.

LIEBLER : What Lenny says is right on target. Different types of buildings call for specific types of plumbing equipment. For example, in high-rise construction, you need to specify pumps for the right pressure.

CSE: How could the plumbing engineer's role be improved? Do they need to be involved earlier in the design or predesign process?

LIEBLER : Absolutely. If we're talking architectural schematic phase, this would be good. I find that more often than not, the architect isn't aware enough of what the plumbing needs will be.

BALDINO : It's even more critical for plumbing engineer [than for others] to be involved early in the project. In fact, one project we did was a success story for just this reason; the team leader got the plumbing designers involved early.

CSE: What's something that plumbing designers, more than other design team members, are able to bring to the table?

BALDINO and LIEBLER : A sense of humor.

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